1. Field of the Invention
The present invention is directed to electromechanical positioners, and more particularly, to the rapid and precise positioning of optical mirrors and gratings.
2. Description of the Prior Art
Segmented mirrors and diffraction gratings of many kinds are well known and widely used. However, most of the prior art positioning methods utilize piezoelectric length and thickness deformations. For example, Final Report "EMRLD Beam Quality Demonstrator Adaptive Optics System", Itek Optical Systems report no. 86-9396-1, March 1986 describes a deformable mirror which uses 341 extension-mode piezoelectric actuators.
In the paper entitled "Electrically Deformable Echelette Grating and its Application to Tunable Laser Resonator", T. Utsunomiya et al, Electronics and Communications in Japan, Vol. 63-C, No. 10, 1980, an electrically deformable echelette grating is disclosed with diffraction characteristics which can be controlled electrically by shear strain of a piezoelectric material. In that disclosure a large number of piezoelectric shear elements are used, and the elements are bonded together. Rotation by shear of the bonded assemblage disclosed in the Utsunomiya et al reference requires rotation of the entire assemblage thereby precluding rapid angular or linear acceleration.